Prison bullying victims are deliberately self-harming to be transferred out of a jail, inspectors have warned.

Inmates at Wealstun prison in West Yorkshire felt unsafe and were often bullied over debts caused by drugs or tobacco, the report said.

Chief inspector of prisons Nick Hardwick said there were examples to support the "disturbing perception among prisoners and staff" that inmates were self-harming to try to persuade authorities to move them to another jail.

"Staff and prisoners alike described a culture of managing bullying by removing the victim to the segregation unit and, in many cases, subsequent transfer out of the prison," he said. "There was little active engagement with prisoners identified as bullies, and no support available for victims beyond an assertiveness course in the education department."

The inspectors found many prisoners felt unsafe. A survey carried out by the prison last February found almost one in four prisoners saw bullying as an issue, with four in five saying the most common reason was drug debts, and three in four citing tobacco debts.

One prisoner said parcels of drugs were constantly "coming over the fence". Another added: "One of the worst jails I've been in for getting into debt - for drugs and alcohol, for example."

Mr Hardwick said the category C training prison, which holds 800 inmates, was "clearly slipping backwards" since the open category D side of the prison closed in 2008.

"The deterioration in safety is the most obvious example but there is a disturbing sense of lack of grip in other areas too," he said. "The issues identified in this report need to be addressed quickly and effectively to prevent them from becoming even more serious."

Michael Spurr, chief executive of the National Offender Management Service (Noms), said: "As the chief inspector acknowledges, the change of role at Wealstun has been challenging.

"I am pleased that the outcomes for prisoners remain reasonably good but accept that the prison needs to improve in a number of key areas. The new governor and his team will develop an action plan to address the weaknesses identified."